Integrated circuits are used in many portable electronic products, such as cell phones, portable computers, voice recorders, etc., as well as in many larger electronic systems, such as cars, planes, industrial control systems, etc. Integrated circuits may include a combination of active devices, passive devices and their interconnections.
Active devices are typically comprised by metal-oxide-semiconductor field-effect transistor (MOSFET) devices, which generally include a semiconductor substrate, having a source, a drain, and a channel located between the source and drain. A gate stack composed of a conductive material (i.e., a gate) and an oxide layer (i.e., a gate oxide) are typically located directly above the channel. During operation, an inversion layer forms a conducting bridge or “channel” between the source and drain when a voltage is applied to the gate. But as MOSFET devices are adapted for higher voltage applications, problems arise with respect to current and voltage output characteristics for these traditional MOSFET devices.
Accordingly, the semiconductor industry developed lateral diffused metal-oxide semiconductor (LDMOS) structures to help ameliorate some of these problems. For example, LDMOS structures solved some of these problems by altering (i.e., by increasing) the length of the drift region, thereby suppressing the shift in the peak electric field to the highly doped drain regions, which can cause an unwanted increase in the substrate current. It will be appreciated by those skilled in the art that unacceptably high substrate current levels can degrade a device's safe operation region.
However, forming an LDMOS structure with a longer/wider drift region will consume more substrate area and create a larger device, which is in direct opposition to the central tenet of modern day semiconductor manufacturing (i.e., decreasing the size of a device). Moreover, a longer/wider drift region can also increase the parasitic capacitance and the on-state resistance (Ron) of the LDMOS device, two conditions which may affect high frequency performance and operating speed of the device. With power MOSFET's finding increasing use in portable electronics and wireless applications, where battery power is at a premium, the trend is understandably toward lower values of Ron.
Thus, a need still remains for a reliable integrated circuit system and method of fabrication, wherein the integrated circuit system exhibits a reduced substrate current, a lower parasitic capacitance, and/or a lower on-state resistance. In view of the ever-increasing commercial competitive pressures, increasing consumer expectations, and diminishing opportunities for meaningful product differentiation in the marketplace, it is increasingly critical that answers be found to these problems. Moreover, the ever-increasing need to save costs, improve efficiencies, and meet such competitive pressures adds even greater urgency to the critical necessity that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.